It's time to pull on the filthy jeans, chip the black nail varnish and find a large mirror to prance in front of: For Ellen has arrived. As tattooed rocker Joby Taylor, Paul Dano is a revelation: self-absorbed, vulnerable, idiotic, charismatic. This is no ordinary rock'n'roll movie though: For Ellen is really about a young man growing up quickly into fatherhood.

Taylor turns up in a small American town to sign divorce papers with an understandably embittered wife; but he groggily realises, in the nick of time, that he would have to give up custody of his 6-year-old daughter. Watching their relationship develop is one of the pleasures of this brilliantly observed film – here's the Guardian's full review of it.

Paul Dano as Joby Taylor

The director of For Ellen is Sundance favourite So Yong Kim, who has created a splash on the indie circuit over the last few years with her first two films, In Between Days and Treeless Mountain. For Ellen turned up at Sundance London last year, after debuting at Sundance proper earlier in 2012, and Kim took time out to speak to me about her – and particularly about how she came up with the main character.

"The English would call him a 'wanker', no?" asks Kim. She's not wrong. "We watched a lot of MTV together, and the Metallica documentary Some Kind of Monster. The way Paul works is to do a lot of preparation. He had to make sure the nail polish was chipped in exactly the right way. Each tattoo had to have a proper story behind it.

Bizarrely, Kim's story started out about the ghost of an old man; you can read how it evolved into its present shape in the rest of the interview, here.